Very odd. I just double-checked with my implementation: I just send “1” for “Manual” and “3” for Automatic.
Can’t be a change in the firmware or the binding because I’m on the latest versions. But then again, …, it’s not exactly the same thermostat, so maybe that’s why. Maybe you have to do the same reverse-engineering than I did.
On a sidenote: Did you check the humongous (but still incomplete) documentation? I linked it here for another reverse-engineering-effort.